For any of several reasons it may be desirable to control the movement of a vehicle as it is being used. For instance, it may be desirable to confine or limit the movement of the vehicle to within a specifically defined area. It may also be desirable to selectively disable the vehicle and thereby prevent its further movement within the defined area. This capability can be particularly important when the vehicle (e.g. a shopping cart) is temporarily loaned or provided to an individual (e.g. a customer) for movement through a defined area (e.g. a shopping center and its contiguous parking lot). Obviously, in such situations, a primary objective is theft prevention.
To prevent the movement of vehicles from a defined area that is relatively large (e.g. several acres), practical considerations tend to dictate that the most cost effective way to control the situation is through the employment of electronic means. This then requires the generation of a signal, and an appropriate response to the signal. For theft prevention purposes, the activating signal needs to be generated at known locations (i.e. at the perimeter of a defined area, or at predetermined locations within the defined area). As is well known, such signals can be transmitted as electromagnetic waves between a transmitter and a receiver.
Depending on how they are to be used, electronic barriers can be established in several different ways. For example, U.S. application Ser. No. 11/386,877, assigned to the same assignee as the present invention, considers activation signals that are transmitted from either above-ground RF beacons or from underground loop antennas (i.e. buried cables). When complex or extended perimeters are involved, however, using only one type transmitter may be less than completely effective. Instead, such situations may be best served using different kinds of antennas. For instance, along extended portions of a perimeter, an underground loop antenna (i.e. buried cable) may be preferable. On the other hand, RF beacons that can direct their beams to locations and areas around structures that would otherwise be difficult to cover by a buried cable may be more cost effective in specific situations. Other aspects also need to be considered. For example, unlike buried cable which is effectively stationary, RF beacons are more easily moved and can be used intermittently at several different locations. In any event, as is well known, underground loop antennas, and above-ground RF beacons, present different installation and different operational considerations. Importantly, different systems require different transmitters and different receivers.
In light of the above, it is an object of the present invention to provide a locking system for disabling a vehicle that interacts with electronic barriers having either above-ground or underground transmitters. Another object of the present invention is to provide a vehicle locking (disabling) system that effectively prevents the removal of a vehicle from within a defined area whenever it encounters an electronic barrier. Yet another object of the present invention is to provide a vehicle locking (disabling) system that can be easily incorporated for use with other electronic inventory assessment and surveillance systems. Another object of the present invention is to provide a vehicle locking system that is easy to use, simple to manufacture, and comparatively cost effective.